In his testimony, Martin said the merger between Dallas-based AT&T and Turner's parent company, Time Warner, would give his company the customer data and scale it needs. He said it'd allow Turner to reach customers in new ways and better compete as Google and Facebook steal away ad dollars from the television industry.

Justice Department attorneys say that Turner, in particular, has programming that rivals must have to compete. Turner networks include CNN , TNT and TBS and they carry live news and sports events like NBA playoffs and NCAA's March Madness. Turner and CBS share broadcasting rights for the college basketball tournament.

Martin, however, made the case why AT&T -- the largest pay-TV company in the country and a major wireless carrier -- is a much-needed partner as the ground shifts in the entertainment industry. He said Turner is playing catch-up to streaming services like Netflix, which can tailor ads to individual customers and get detailed data that helps it develop popular programming.

Martin said Turner has asked distributors for the data and they say no.

He said Turner's subscriber and advertising revenue is under pressure as more households cut cable and satellite TV. And he said Turner wants to distribute its networks as widely as possible, but has faced resistance.

For example, Martin said, Dish Chairman Charlie Ergen saw Turner's deal with live streaming service Sony PlayStation Vue as a threat. He said Ergen reacted angrily in 2014 when Time Warner-owned HBO announced it was launching direct-to-consumer streaming service, HBO Now. And he said Ergen wanted Turner to make a commitment that it wouldn't launch its own direct-to-consumer streaming service.

Soon after, Martin said Dish and Turner reached an impasse in contract negotiations. Ergen called to tell Martin he was taking down Turner programming. The blackout for Dish customers lasted about a month.

But Justice Department attorney Eric Welsh dismissed the portrayal of Turner as a helpless wholesaler and struggling programmer. He pointed to Turner's double-digit annual rate increases for distributors and said the charges for some of its networks, like TBS and TNT, are far above the industry average.

He referred to the approximately $1.1 billion fee that Turner pays the NBA to carry 64 games. The high-dollar amount stunned U.S. District Judge Richard Leon, who is presiding over the case. He checked to make sure the lawyer meant billion, not million.

Welsh said Turner already uses its programming as leverage in negotiations. In 2014, he said, it timed a Dish contract to expire during March Madness.

And he said Turner doesn't need AT&T to innovate. Before the merger's announcement, Welsh said Turner planned to acquire ad companies, but dropped the idea when AT&T announced it would buy Time Warner. Turner has two internet-based streaming services, FilmStruck and Boomerang, and this week, it announced a third: Bleacher Report Live, a sports streaming service, which will launch in April.

The trial continues Thursday. John Hauser, a Massachusetts Institute of Technology marketing professor, and Greg Rigdon, Comcast's executive vice president of content acquisition, are expected to testify.